NEW YORK (Reuters Health) - Even though testing has so far raised no "red flags" regarding safety of potential swine flu vaccines, surveys and focus groups show that healthcare workers and members of the public may be leery of being getting shots when supplies become available this fall.

Writing in the BMJ, Dr. Paul K. S. Chan and associates at the Chinese University of Hong Kong note that "in nearly all countries with a (pandemic) preparedness plan, healthcare workers are listed as the priority group for mass vaccination."

In May of this year when the WHO alert level had been raised to phase 5, meaning a pandemic was imminent, researchers distributed 810 questionnaires to public hospital workers, primarily doctors and nurses in Hong Kong. (The level was later raised to phase 6, pandemic.)

Less than half (48%) of the 389 workers who returned the questionnaires intended to accept pre-pandemic H1N1 vaccination. The most common reason for refusal was potential side effects, followed by questions about the vaccine's efficacy and the conviction that it was "not yet the right time to be vaccinated."

"This is particularly surprising in a city where the SARS outbreak had such a huge impact," Dr. Chan's team points out.

Those with a history of seasonal flu vaccination were more likely to be willing to be vaccinated.

In an accompanying editorial, Dr. Rachel Jordan, from the University of Birmingham, and Dr. Andrew Hayward, from the University College of London, write that to increase vaccine use, "use of convenient mobile systems, monitoring and feedback systems, and 'opt-out' systems (where healthcare workers need to indicate their reasons for not accepting the vaccine) show promise."

In a separate article published online in the Emerging Health Threats Journal, very few of 85 focus group participants in British Columbia said they would be willing to be vaccinated in the event of a pandemic. Very few people said they or their children would definitely get vaccinated, the authors report.

Many participants were concerned about the risk of infection versus the risks involved in using newly developed vaccines, write Dr. Natalie Henrich of the University of British Columbia and Dr. Bev J. Holmes at Simon Fraser University, both in Vancouver. "Participants were hesitant to use the novel vaccines (due to) concern that unsafe pharmaceuticals may be rushed to market during the health crisis," the authors said.

The focus groups were conducted before the current H1N1 pandemic, in 2006 and 2007.

Instead, many individuals believed they could protect themselves through their own behavior, including frequent handwashing, staying away from crowded places and sick people, and eating well to maintain their immune systems.